1. Field of the Invention
This invention relates to an intake system for a V-type engine, and more particularly to an intake system for a V- type engine which supercharges the engine by kinetic effect of intake air.
2. Description of the Prior Art
As disclosed, for instance, in Japanese Unexamined Pat. Publication Nos. 62(1987)-91621, 62(1987)-162723 and 63(1988)-263319, and U.S. Pat. No. 4649871, there has been known an intake system for an internal combustion engine which is arranged to supercharge the engine by inertia effect of intake air. In such an inertia supercharging intake system, the engine speed range in which the inertia supercharging effect can be obtained depends upon the length of the intake passage between the intake port of each cylinder and the portion at which the pressure wave generated at the intake port and propagated away from the intake port is reflected toward the intake port. Accordingly, in order to obtain the inertia supercharging effect in a wider engine speed range, the effective length between the intake port and the pressure wave reflecting portion, which is generally in the form of an enlarged volume chamber, must be changed with the engine speed. For example, when a pair of enlarged volume chambers are provided at different distances from the intake port and the intake passage upstream of the intake port is selectively communicated with one of the enlarged volume chambers according to the engine speed, the inertia supercharging effect can be obtained in a wider engine speed range. However, this approach gives rise to a problem that the intake system is apt to be complicated and cumbersome. This problem is especially serious in the case of a V-type engine.